1575161221 has 2 divisors, whose sum is σ = 1575161222. Its totient is φ = 1575161220.

The previous prime is 1575161207. The next prime is 1575161257. The reversal of 1575161221 is 1221615751.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1496838721 + 78322500 = 38689^2 + 8850^2 .

It is a cyclic number.

It is not a de Polignac number, because 1575161221 - 2²¹ = 1573064069 is a prime.

It is a super-2 number, since 2×1575161221² = 4962265744284421682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1575161321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 787580610 + 787580611.

It is an arithmetic number, because the mean of its divisors is an integer number (787580611).

Almost surely, 2^1575161221 is an apocalyptic number.

It is an amenable number.

1575161221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1575161221 is an equidigital number, since it uses as much as digits as its factorization.

1575161221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4200, while the sum is 31.

The square root of 1575161221 is about 39688.3008076688. The cubic root of 1575161221 is about 1163.5230834089.

Adding to 1575161221 its reverse (1221615751), we get a palindrome (2796776972).

The spelling of 1575161221 in words is "one billion, five hundred seventy-five million, one hundred sixty-one thousand, two hundred twenty-one".